Sustainably produced biofuels are an alternative to fossil fuels and may help to alleviate the depletion of easily accessible fossil fuel stocks while avoiding fossil fuel-associated pollution and greenhouse gas emission, thus satisfying a rising demand for affordable energy in a sustainable way. However, the widespread implementation of biofuel production has been thwarted by several drawbacks of current production methods, for example the competition of biofuel-producing plants with food crops for agriculturally valuable acreage, or the use of industrial substrates with only limited supply as carbon sources.